There are known to be several compounds belonging to the class of alkyl-sulphonyl chlorides and arylalkyl-sulphonyl chlorides, which find a great number of applications as intermediates or catalysts in organic syntheses, as additives and intermediates for the oil industry, as auxiliaries for the textile industry, as additives for the rubber industry, as pesticides and, particularly, as additives for the tanning industry, and this is due to the high reactivity of the sulphonyl chloride group --SO.sub.2 Cl.
Sulphonyl chlorides can be prepared by direct sulphochlorination of the corresponding hydrocarbons with various reactants such as, for example, mixtures of Cl.sub.2 +SO.sub.2 or sulphuryl chloride SO.sub.2 Cl.sub.2, and in many cases the reaction is activated with actinic radiations. These methods generally give good results for the first terms of the series, as methan-sulphonyl chloride and ethan-sulphonyl chloride; whereas they give unsatisfactory results for preparing higher terms, due to the forming of mono-, di- and polysulphonyl chlorides, and also by-products as unsaturated chlorides and hydrocarbons, which give rise to very complex mixtures from which the pure compounds are difficult to separate.
There are also known to be methods for preparing sulphonyl chlorides having a defined structure, based on the oxidation-chlorination--carried out with gaseous chlorine in the presence of water--of sulpho-organic compounds belonging to various functional classes, as mercaptans, disulphides, thiocyanates, isothiouronium salts, Bunte salts and others. In the case of using dimethyl disulphide as a starting compound, methan-sulphonyl chloride can be easily obtained, with excellent yields, through the reaction: ##STR1##
Nevertheless, in general, the other alkyl-disulphides and the other sulpho-organic compounds are of difficult and too costly preparation, or else they supply the corresponding sulphonyl chlorides in preparatively and thus economically unacceptable yields, and this mainly in the case of higher terms.